1. Field of Invention
This invention relates to an electro-optical system for accurately determining the electrical voltage between two spaced objects. More specifically, the invention relates to a system which utilizes an electro-optical crystal with a fourfold axis of rotary inversion which exhibits birefringence in proportion to the magnitude of an applied electric field. In particular, it relates to generating two electrical signals in quadrature from parallel beams of collimated polarized light which are passed through the electro-optical crystal and retarded by fractional waveplates to produce a relative retardation of 1/4 wave. Finally, the invention relates to deriving a representation of the voltage waveform generating the field applied to the electro-optic crystal from the two electrical signals in quadrature utilizing a digital computer.